Add MOLECULE_SUFFIX for naming uniqueness in molecule.yml

[decentral1se]

Issue Type

• Feature request

Molecule and Ansible details

Latest

Molecule installation method (one of):

• pip

Ansible installation method (one of):

• pip

Desired Behavior

My molecule.yml looks like so.

---
dependency:
  name: galaxy
driver:
  name: hetznercloud
platforms:
  - name: "myrolename-${INSTANCE_UUID}"
    server_type: cx11
    image: debian-10
provisioner:
  name: ansible
lint: |
  set -e
  yamllint -c ../../.yamllint.yml .
  ansible-lint -c ../../.ansible-lint.yml

Where I export INSTANCE_UUID into the environment in order to have my VPS instance names not clash when different people are running builds that should still be run in serial execution. Therefore, --parallel is not an option here.

So, I think it would be nice to avoid this step and have some sort of "magic variable" exposed from molecule side so that I can use it as needed in the instance name through variable expansion.

If in agreement, I'll send a patch.

[ssbarnea]

I am ok to add a UUID variable which is saved inside the cache (gets lost when running molecule reset).

I am not yet sure if INSTANCE_UUID is a clear enough name, one that may not overlap with a random environment variable used by the user. Maybe someone has a better idea, I do not at this moment.

We need to be sure that this feature does not break the destroy feature, so we need a test for it.

I wonder if we could maybe expose something like MOLECULE_SUFFIX which would have the same purpose but could allow us to enable/disable the feature, without changing the code.

platforms:
  - name: "myrolename${MOLECULE_SUFFIX:}"

For example MOLECULE_SUFFIX would default to something like -xf3s which is randomly generated and stored inside cache. The big benefit on this that we could have an empty suffix if we want. Appending read UUIDs to different resource names is not always possible because they do all have a length limit and we already encountered problems container limits in that area. That is why I am inclined to believe that maybe UUID could be misleading.

[decentral1se]

Oh yeah, MOLECULE_SUFFIX is a pretty good strategy. Agree on your points.

OK, this is a ready for a pull request!

[decentral1se]

Related https://github.com/ansible-community/molecule/issues/2462.